1. Field of Invention
The invention relates to the field of wireless communications and more specifically to an enhanced wireless audio system.
2. Description of the Related Prior Art
As shown in FIG. 1, in its simplest form, a typical portable digital wireless audio system comprises two devices: a personal wireless audio player 100 which communicates with a wireless remote control 140 or wireless headphones 120. The audio data is a unidirectional stream from personal wireless audio player 100, the audio source, to wireless headphones 120, the audio sink. In the case of wireless remote control 140, personal wireless audio player 100, the audio source, may also send LCD display information to wireless remote control 140, the audio sink, and the audio sink will return packets containing key-press information (e.g. audio track selection).
Current radio technology that has the capacity to carry high quality stereo audio consumes too much power to make the use of wireless headphone 120 or wireless remote control 140 in conjunction with wireless personal audio player 100 successful in the marketplace. Presently, most personal audio players such as CD players, Mini-Disk players, and MP3 players are not wireless with a headphone or remote control being corrected to the player via a hard wire. Such personal audio players are intended to be mobile, (i.e. easily carried by the user) and are powered from a battery to allow for such portability. Currently, the vast majority of such personal audio products use one battery and the subtending headphone (and possibly remote control) receive their power from the battery in the player through the hard wire.
The hard wire connecting the player to the headphone and/or remote control is often an inconvenience to the user. For example, when the user wishes to put the player into a pocket, backpack or briefcase, the wires to the headphone or remote control must extend out to connect to the headphone or remote control. In addition, the wires tend to get tangled or snagged.
If the wire extending from the player is eliminated, the headphone/remote control then require their own power and one of the components that the battery will have to supply is the radio interface. Personal audio manufacturers have stated that wireless headphones and remote controls must be small, lightweight, and operate for 100 hours before the battery needs to be replaced. 100 hours of operation from a 450 mAHr 3v supply (2 CR2032 Li coin-cell batteries) requires the headphone and/or remote control to consume an average of no more than about 6 mA from a 2v supply, of which about 4 mA is available for the radio. Current radio technology consumes on the order of 20 mA or more so does not meet the standard suggested by manufacturers.
While power consumption is the main hurdle facing wireless (i.e. radio) solutions for personal audio applications, such solutions must also deliver high quality audio, deal with interference from a plethora of other radio sources, and be small and inexpensive.